if (condition) statement<\/code><\/p>\n\n\n\n\u8fd9\u91cc condition \u662f\u4e00\u4e2a\u5c06\u88ab\u8ba1\u7b97\u7684\u8868\u8fbe\u5f0f\uff08expression\uff09\u3002\u5982\u679c\u8868\u8fbe\u5f0f\u503c\u4e3a\u771f\uff0c\u5373\u6761\u4ef6(condition)\u4e3atrue\uff0cstatement \u5c06\u88ab\u6267\u884c\u3002\u5426\u5219\uff0cstatement \u5c06\u88ab\u5ffd\u7565\uff08\u4e0d\u88ab\u6267\u884c\uff09\uff0c\u7a0b\u5e8f\u4ece\u6574\u4e2a\u6761\u4ef6\u7ed3\u6784\u4e4b\u540e\u7684\u4e0b\u4e00\u6761\u8bed\u53e5\u7ee7\u7eed\u6267\u884c\u3002<\/p>\n\n\n\n
\u4f8b\u5982\uff0c\u4ee5\u4e0b\u7a0b\u5e8f\u6bb5\u5b9e\u73b0\u53ea\u6709\u5f53\u53d8\u91cfx\u5b58\u50a8\u7684\u503c\u786e\u5b9e\u4e3a100\u7684\u65f6\u5019\u624d\u8f93\u51fa”x is 100″\uff1aif (x == 100)
cout << “x is 100”;<\/p>\n\n\n\n
\u5982\u679c\u6211\u4eec\u9700\u8981\u5728\u6761\u4ef6condition\u4e3a\u771ftrue\u7684\u65f6\u5019\u6267\u884c\u4e00\u6761\u4ee5\u4e0a\u7684\u8bed\u53e5\uff0c\u6211\u4eec\u53ef\u4ee5\u82b1\u62ec\u53f7{}\u5c06\u8bed\u53e5\u62ec\u8d77\u6765\u7ec4\u6210\u4e00\u4e2a\u8bed\u53e5\u5757\uff1aif (x == 100)
{
cout << “x is “;
cout << x;
}<\/p>\n\n\n\n
\u6211\u4eec\u53ef\u4ee5\u7528\u5173\u952e\u5b57else \u6765\u6307\u5b9a\u5f53\u6761\u4ef6\u4e0d\u80fd\u88ab\u6ee1\u8db3\u65f6\u9700\u8981\u6267\u884c\u7684\u8bed\u53e5\uff0c\u5b83\u9700\u8981\u548cif \u4e00\u8d77\u4f7f\u7528\uff0c\u5f62\u5f0f\u662f\uff1aif (condition) statement1 else statement2<\/code><\/p>\n\n\n\n\u4f8b\u5982\uff1aif (x == 100)
cout << “x is 100”;
else
cout << “x is not 100”;<\/p>\n\n\n\n
\u4ee5\u4e0a\u7a0b\u5e8f\u5982\u679cx\u7684\u503c\u4e3a100\uff0c\u5219\u5728\u5c4f\u5e55\u4e0a\u6253\u51fax is 100\uff0c\u5982\u679cx\u4e0d\u662f100\uff0c\u800c\u4e14\u4e5f\u53ea\u6709\u5728x\u4e0d\u662f100\u7684\u65f6\u5019\uff0c\u5c4f\u5e55\u4e0a\u5c06\u6253\u51fax is not 100\u3002<\/p>\n\n\n\n
\u591a\u4e2aif + else \u7684\u7ed3\u6784\u88ab\u8fde\u63a5\u8d77\u6765\u4f7f\u7528\u6765\u5224\u65ad\u6570\u503c\u7684\u8303\u56f4\u3002\u4ee5\u4e0b\u4f8b\u5b50\u663e\u793a\u4e86\u5982\u4f55\u7528\u5b83\u6765\u5224\u65ad\u53d8\u91cf x\u4e2d\u5f53\u524d\u5b58\u50a8\u7684\u6570\u503c\u662f\u6b63\u503c\uff0c\u8d1f\u503c\u8fd8\u662f\u65e2\u4e0d\u6b63\u4e5f\u4e0d\u8d1f\uff0c\u5373\u7b49\u4e8e0 \u3002if (x > 0)
cout << “x is positive”;
else if (x < 0)
cout << “x is negative”;
else
cout << “x is 0”;<\/p>\n\n\n\n
\u8bb0\u4f4f\u5f53\u6211\u4eec\u9700\u8981\u6267\u884c\u591a\u6761\u8bed\u53e5\u65f6\uff0c\u5fc5\u987b\u4f7f\u7528\u82b1\u62ec\u53f7{}\u5c06\u5b83\u4eec\u62ec\u8d77\u6765\u4ee5\u7ec4\u6210\u4e00\u4e2a\u8bed\u53e5\u5757block of instructions\u3002<\/p>\n\n\n\n
\u91cd\u590d\u7ed3\u6784 Iteration structures \u6216\u5faa\u73afloops<\/h3>\n\n\n\n
\u5faa\u73afLoops \u7684\u76ee\u7684\u662f\u91cd\u590d\u6267\u884c\u4e00\u7ec4\u8bed\u53e5\u4e00\u5b9a\u7684\u6b21\u6570\u6216\u76f4\u5230\u6ee1\u8db3\u67d0\u79cd\u6761\u4ef6\u3002<\/p>\n\n\n\n
while \u5faa\u73af<\/h4>\n\n\n\n
\u683c\u5f0f\u662f\uff1awhile (\u8868\u8fbe\u5f0fexpression) \u8bed\u53e5statement<\/code><\/p>\n\n\n\n\u5b83\u7684\u529f\u80fd\u662f\u5f53expression \u7684\u503c\u4e3a\u771ftrue\u65f6\u91cd\u590d\u6267\u884cstatement\u3002<\/p>\n\n\n\n
\u4f8b\u5982\uff0c\u4e0b\u9762\u6211\u4eec\u5c06\u7528while\u5faa\u73af\u6765\u5199\u4e00\u4e2a\u5012\u8ba1\u6570\u7a0b\u5e8f\uff1a<\/p>\n\n\n\n\/\/ custom countdown using while
#include <iostream.h>
int main ()
{
int n;
cout << “Enter the starting number > “;
cin >> n;
while (n>0) {
cout << n << “, “;
–n;
}
cout << “FIRE!”;
return 0;
}<\/td> Enter the starting number > 8
8, 7, 6, 5, 4, 3, 2, 1, FIRE!<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n\u7a0b\u5e8f\u5f00\u59cb\u65f6\u63d0\u793a\u7528\u6237\u8f93\u5165\u4e00\u4e2a\u5012\u8ba1\u6570\u7684\u521d\u59cb\u503c\u3002\u7136\u540ewhile \u5faa\u73af\u5f00\u59cb\uff0c\u5982\u679c\u7528\u6237\u8f93\u5165\u7684\u6570\u503c\u6ee1\u8db3\u6761\u4ef6n>0 (\u5373 n \u6bd40 \u5927)\uff0c\u540e\u9762\u8ddf\u7684\u8bed\u53e5\u5757\u5c06\u4f1a\u88ab\u6267\u884c\u4e00\u5b9a\u7684\u6b21\u6570\uff0c\u76f4\u5230\u6761\u4ef6 (n>0) \u4e0d\u518d\u6ee1\u8db3\uff08\u53d8\u4e3afalse\uff09\u3002<\/p>\n\n\n\n
\u4ee5\u4e0a\u7a0b\u5e8f\u7684\u6240\u6709\u5904\u7406\u8fc7\u7a0b\u53ef\u4ee5\u7528\u4ee5\u4e0b\u7684\u63cf\u8ff0\u6765\u89e3\u91ca\uff1a<\/p>\n\n\n\n
\u4ecemain<\/strong>\u5f00\u59cb\uff1a<\/p>\n\n\n\n- \u7528\u6237\u8f93\u5165\u4e00\u4e2a\u6570\u503c\u8d4b\u7ed9n.<\/li>
- while\u8bed\u53e5\u68c0\u67e5(n>0)\u662f\u5426\u6210\u7acb\uff0c\u8fd9\u65f6\u6709\u4e24\u79cd\u53ef\u80fd\uff1a
- true: \u6267\u884cstatement (\u5230\u7b2c3\u6b65)<\/li>
- false: \u8df3\u8fc7statement. \u7a0b\u5e8f\u76f4\u63a5\u6267\u884c\u7b2c5\u6b65.<\/li><\/ul><\/li>
- \u6267\u884cstatement:
cout << n << \", \";
--n;<\/code>(\u5c06n \u7684\u503c\u6253\u5370\u5728\u5c4f\u5e55\u4e0a\uff0c\u7136\u540e\u5c06n \u7684\u503c\u51cf1).<\/li>- \u8bed\u53e5\u5757\u7ed3\u675f\uff0c\u81ea\u52a8\u8fd4\u56de\u7b2c2\u6b65\u3002<\/li>
- \u7ee7\u7eed\u6267\u884c\u8bed\u53e5\u5757\u4e4b\u540e\u7684\u7a0b\u5e8f\uff1a\u6253\u5370 FIRE! \uff0c\u7a0b\u5e8f\u7ed3\u675f\u3002<\/li><\/ol>\n\n\n\n
\u6211\u4eec\u5fc5\u987b\u8003\u8651\u5230\u5faa\u73af\u5fc5\u987b\u5728\u67d0\u4e2a\u70b9\u7ed3\u675f\uff0c\u56e0\u6b64\u5728\u8bed\u53e5\u5757\u4e4b\u5185\uff08loop\u7684statement\u4e4b\u5185) \u6211\u4eec\u5fc5\u987b\u63d0\u4f9b\u4e00\u4e9b\u65b9\u6cd5\u4f7f\u5f97\u6761\u4ef6condition \u53ef\u4ee5\u5728\u67d0\u4e2a\u65f6\u523b\u53d8\u4e3a\u5047 false\uff0c\u5426\u5219\u5faa\u73af\u5c06\u65e0\u9650\u91cd\u590d\u4e0b\u53bb\u3002\u5728\u8fd9\u4e2a\u4f8b\u5b50\u91cc\uff0c\u6211\u4eec\u7528\u8bed\u53e5–n;\u4f7f\u5f97\u5faa\u73af\u5728\u91cd\u590d\u4e00\u5b9a\u7684\u6b21\u6570\u540e\u53d8\u4e3afalse \uff1a\u5f53 n \u53d8\u4e3a0\uff0c \u5012\u8ba1\u6570\u7ed3\u675f\u3002<\/p>\n\n\n\n
do-while \u5faa\u73af<\/h4>\n\n\n\n
\u683c\u5f0f\uff1ado \u8bed\u53e5statement while (\u6761\u4ef6condition);<\/code><\/p>\n\n\n\n\u5b83\u7684\u529f\u80fd\u4e0ewhile \u5faa\u73af\u4e00\u62b9\u4e00\u6837\uff0c\u9664\u4e86\u5728do-while\u5faa\u73af\u4e2d\u662f\u5148\u6267\u884cstatement \u7136\u540e\u624d\u68c0\u67e5\u6761\u4ef6condition \uff0c\u800c\u4e0d\u60f3while\u5faa\u73af\u4e2d\u5148\u68c0\u67e5\u6761\u4ef6\u7136\u540e\u624d\u6267\u884cstatement\u3002\u8fd9\u6837\uff0c\u5373\u4f7f\u6761\u4ef6condition\u4ece\u6765\u6ca1\u6709\u88ab\u6ee1\u8db3\u8fc7\uff0cstatement \u4ecd\u81f3\u5c11\u88ab\u6267\u884c\u4e00\u6b21\u3002\u4f8b\u5982\uff0c\u4e0b\u9762\u7684\u7a0b\u5e8f\u91cd\u590d\u8f93\u51fa\uff08echoes\uff09\u7528\u6237\u8f93\u5165\u7684\u4efb\u4f55\u6570\u503c\uff0c\u76f4\u5230\u7528\u6237\u8f93\u51650\u4e3a\u6b62\u3002<\/p>\n\n\n\n\/\/ number echoer
#include <iostream.h>
int main ()
{
unsigned long n;
do {
cout << “Enter number (0 to end): “;
cin >> n;
cout << “You entered: ” << n << “\\n”;
} while (n != 0);
return 0;
}<\/td> Enter number (0 to end): 12345
You entered: 12345
Enter number (0 to end): 160277
You entered: 160277
Enter number (0 to end): 0
You entered: 0<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\ndo-while<\/em> \u5faa\u73af\u901a\u5e38\u88ab\u7528\u5728\u5224\u65ad\u5faa\u73af\u7ed3\u675f\u7684\u6761\u4ef6\u662f\u5728\u5faa\u73af\u8bed\u53e5\u5185\u90e8\u88ab\u51b3\u5b9a\u7684\u60c5\u51b5\u4e0b\uff0c\u6bd4\u5982\u4ee5\u4e0a\u7684\u4f8b\u5b50\uff0c\u5728\u5faa\u73af\u7684\u8bed\u53e5\u5757\u5185\u7528\u6237\u7684\u8f93\u5165\u51b3\u5b9a\u4e86\u5faa\u73af\u662f\u5426\u7ed3\u675f\u3002\u5982\u679c\u7528\u6237\u6c38\u8fdc\u4e0d\u8f93\u51650\uff0c\u5219\u5faa\u73af\u6c38\u8fdc\u4e0d\u4f1a\u7ed3\u675f\u3002<\/p>\n\n\n\nfor \u5faa\u73af<\/h4>\n\n\n\n
\u683c\u5f0f\u662f\uff1afor (initialization; condition; increase) statement;<\/code><\/p>\n\n\n\n\u5b83\u7684\u4e3b\u8981\u529f\u80fd\u662f\u5f53\u6761\u4ef6condition \u4e3a\u771ftrue<\/strong>\u65f6\u91cd\u590d\u6267\u884c\u8bed\u53e5statement \uff0c\u7c7b\u4f3cwhile \u5faa\u73af\u3002\u4f46\u9664\u6b64\u4e4b\u5916\uff0cfor \u8fd8\u63d0\u4f9b\u4e86\u5199\u521d\u59cb\u5316\u8bed\u53e5initialization \u548c\u589e\u503c\u8bed\u53e5increase \u7684\u5730\u65b9\u3002\u56e0\u6b64\u8fd9\u79cd\u5faa\u73af\u7ed3\u6784\u662f\u7279\u522b\u4e3a\u6267\u884c\u7531\u8ba1\u6570\u5668\u63a7\u5236\u7684\u5faa\u73af\u800c\u8bbe\u8ba1\u7684\u3002<\/p>\n\n\n\n\u5b83\u6309\u4ee5\u4e0b\u65b9\u5f0f\u5de5\u4f5c\uff1a<\/p>\n\n\n\n
- \u6267\u884c\u521d\u59cb\u5316initialization \u3002\u901a\u5e38\u5b83\u662f\u8bbe\u7f6e\u4e00\u4e2a\u8ba1\u6570\u5668\u53d8\u91cf\uff08counter variable\uff09\u7684\u521d\u59cb\u503c\uff0c\u521d\u59cb\u5316\u4ec5\u88ab\u6267\u884c\u4e00\u6b21\u3002<\/li>
- \u68c0\u67e5\u6761\u4ef6condition \uff0c\u5982\u679c\u6761\u4ef6\u4e3a\u771ftrue\uff0c\u7ee7\u7eed\u5faa\u73af\uff0c\u5426\u5219\u5faa\u73af\u7ed3\u675f\u5faa\u73af\u4e2d\u8bed\u53e5statement \u88ab\u8df3\u8fc7\u3002<\/li>
- \u6267\u884c\u8bed\u53e5statement \u3002\u50cf\u4ee5\u524d\u4e00\u6837\uff0c\u5b83\u53ef\u4ee5\u662f\u4e00\u4e2a\u5355\u72ec\u7684\u8bed\u53e5\uff0c\u4e5f\u53ef\u4ee5\u662f\u4e00\u4e2a\u7531\u82b1\u62ec\u53f7{ }\u62ec\u8d77\u6765\u7684\u8bed\u53e5\u5757\u3002<\/li>
- \u6700\u540e\u589e\u503c\u57df\uff08increase field\uff09\u4e2d\u7684\u8bed\u53e5\u88ab\u6267\u884c\uff0c\u5faa\u73af\u8fd4\u56de\u7b2c2\u6b65\u3002\u6ce8\u610f\u589e\u503c\u57df\u4e2d\u53ef\u80fd\u662f\u4efb\u4f55\u8bed\u53e5\uff0c\u800c\u4e0d\u4e00\u5b9a\u53ea\u662f\u5c06\u8ba1\u6570\u5668\u589e\u52a0\u7684\u8bed\u53e5\u3002\u4f8b\u5982\u4e0b\u9762\u7684\u4f8b\u5b50\u4e2d\u8ba1\u6570\u5668\u5b9e\u9645\u4e3a\u51cf1\uff0c\u800c\u4e0d\u662f\u52a01\u3002<\/li><\/ol>\n\n\n\n
\u4e0b\u9762\u662f\u7528for\u5faa\u73af\u5b9e\u73b0\u7684\u5012\u8ba1\u6570\u7684\u4f8b\u5b50\uff1a<\/p>\n\n\n\n\/\/ countdown using a for loop
#include <iostream.h>
int main ()
{
for (int n=10; n>0; n–) {
cout << n << “, “;
}
cout << “FIRE!”;
return 0;
}<\/td> 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, FIRE!<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n\u521d\u59cb\u5316initialization \u548c\u589e\u503cincrease \u57df\u662f\u53ef\u9009\u7684\uff08\u5373\u53ef\u4ee5\u4e3a\u7a7a\uff09\u3002\u4f46\u8fd9\u4e9b\u57df\u4e3a\u7a7a\u7684\u65f6\u5019\uff0c\u5b83\u4eec\u548c\u5176\u4ed6\u57df\u4e4b\u95f4\u95f4\u9694\u7684\u5206\u53f7\u4e0d\u53ef\u4ee5\u7701\u7565\u3002\u4f8b\u5982\u6211\u4eec\u53ef\u4ee5\u5199\uff1afor (;n<10;)\u6765\u8868\u793a\u6ca1\u6709\u521d\u59cb\u5316\u548c\u589e\u503c\u8bed\u53e5\uff1b\u6216for (;n<10;n++) \u6765\u8868\u793a\u6709\u589e\u503c\u8bed\u53e5\u4f46\u6ca1\u6709\u521d\u59cb\u5316\u8bed\u53e5\u3002<\/p>\n\n\n\n
\u53e6\u5916\u6211\u4eec\u4e5f\u53ef\u4ee5\u5728for\u5faa\u73af\u521d\u59cb\u5316\u6216\u589e\u503c\u57df\u4e2d\u653e\u4e00\u6761\u4ee5\u4e0a\u7684\u8bed\u53e5\uff0c\u4e2d\u95f4\u7528\u9017\u53f7 coma(,)\u9694\u5f00\u3002\u4f8b\u5982\u5047\u8bbe\u6211\u4eec\u60f3\u5728\u5faa\u73af\u4e2d\u521d\u59cb\u5316\u4e00\u4e2a\u4ee5\u4e0a\u7684\u53d8\u91cf\uff0c\u53ef\u4ee5\u7528\u4ee5\u4e0b\u7684\u7a0b\u5e8f\u6765\u5b9e\u73b0\uff1afor ( n=0, i=100 ; n!=i ; n++, i– )
{
\/\/ whatever here…
}<\/p>\n\n\n\n
\u8fd9\u4e2a\u5faa\u73af\u5c06\u88ab\u6267\u884c50 \u6b21\uff0c\u5982\u679cn \u548ci \u5728\u5faa\u8fd8\u5185\u90e8\u90fd\u4e0d\u88ab\u6539\u53d8\u7684\u8bdd\uff1a<\/p>\n\n\n\n![\"\"\/](\"http:\/\/www.prglab.com\/cms\/media\/images\/cplusplus\/img2-1-1.gif\")
<\/figure>\n\n\n\nn<\/strong>\u521d\u59cb\u503c\u4e3a0<\/strong>\uff0ci<\/strong>\u521d\u59cb\u503c\u4e3a100<\/strong>\uff0c\u6761\u4ef6\u662f(n!=i)<\/strong>(\u5373n<\/strong>\u4e0d\u80fd\u7b49\u4e8ei<\/strong>)\u3002\u56e0\u4e3a\u6bcf\u6b21\u5faa\u73afn<\/strong>\u52a01<\/strong>\uff0c\u800c\u4e14i<\/strong>\u51cf1<\/strong>\uff0c\u5faa\u73af\u7684\u6761\u4ef6\u5c06\u4f1a\u5728\u7b2c50\u6b21\u5faa\u73af\u4e4b\u540e\u53d8\u4e3a\u5047false<\/strong>\uff08n<\/strong> \u548c i<\/strong> \u90fd\u7b49\u4e8e50<\/strong>\uff09\u3002<\/p>\n\n\n\n\u5206\u652f\u63a7\u5236\u548c\u8df3\u8f6c(Bifurcation of control and jumps)<\/h3>\n\n\n\nbreak \u8bed\u53e5<\/h4>\n\n\n\n
\u901a\u8fc7\u4f7f\u7528break<\/strong>\u8bed\u53e5\uff0c\u5373\u4f7f\u5728\u7ed3\u675f\u6761\u4ef6\u6ca1\u6709\u6ee1\u8db3\u7684\u60c5\u51b5\u4e0b\uff0c\u6211\u4eec\u4e5f\u53ef\u4ee5\u8df3\u51fa\u4e00\u4e2a\u5faa\u73af\u3002\u5b83\u53ef\u4ee5\u88ab\u7528\u6765\u7ed3\u675f\u4e00\u4e2a\u65e0\u9650\u5faa\u73af\uff08infinite loop\uff09\uff0c\u6216\u5f3a\u8feb\u5faa\u73af\u5728\u5176\u81ea\u7136\u7ed3\u675f\u4e4b\u524d\u7ed3\u675f\u3002\u4f8b\u5982\uff0c\u6211\u4eec\u60f3\u8981\u5728\u5012\u8ba1\u6570\u81ea\u7136\u7ed3\u675f\u4e4b\u524d\u5f3a\u8feb\u5b83\u505c\u6b62\uff08\u4e5f\u8bb8\u56e0\u4e3a\u4e00\u4e2a\u5f15\u64ce\u6545\u969c\uff09\uff1a<\/p>\n\n\n\n\/\/ break loop example
#include <iostream.h>
int main ()
{
int n;
for (n=10; n>0; n–) {
cout << n << “, “;
if (n==3)
{
cout << “countdown aborted!”;
break;
}
return 0;
}<\/td> 10, 9, 8, 7, 6, 5, 4, 3, countdown aborted!<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\ncontinue \u8bed\u53e5<\/h4>\n\n\n\n
continue<\/strong>\u8bed\u53e5\u4f7f\u5f97\u7a0b\u5e8f\u8df3\u8fc7\u5f53\u524d\u5faa\u73af\u4e2d\u5269\u4e0b\u7684\u90e8\u5206\u800c\u76f4\u63a5\u8fdb\u5165\u4e0b\u4e00\u6b21\u5faa\u73af\uff0c\u5c31\u597d\u50cf\u5faa\u73af\u4e2d\u8bed\u53e5\u5757\u7684\u7ed3\u5c3e\u5df2\u7ecf\u5230\u4e86\u4f7f\u5f97\u5faa\u73af\u8fdb\u5165\u4e0b\u4e00\u6b21\u91cd\u590d\u3002\u4f8b\u5982\uff0c\u4e0b\u9762\u4f8b\u5b50\u4e2d\u5012\u8ba1\u6570\u65f6\u6211\u4eec\u5c06\u8df3\u8fc7\u6570\u5b575\u7684\u8f93\u51fa\uff1a<\/p>\n\n\n\n\/\/ continue loop example
#include <iostream.h>
int main ()
{
for (int n=10; n>0; n–) {
if (n==5) continue;
cout << n << “, “;
}
cout << “FIRE!”;
return 0;
}<\/td> 10, 9, 8, 7, 6, 4, 3, 2, 1, FIRE!<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\ngoto \u8bed\u53e5<\/h4>\n\n\n\n
\u901a\u8fc7\u4f7f\u7528goto\u8bed\u53e5\u53ef\u4ee5\u4f7f\u7a0b\u5e8f\u4ece\u4e00\u70b9\u8df3\u8f6c\u5230\u53e6\u5916\u4e00\u70b9\u3002\u4f60\u5fc5\u987b\u8c28\u614e\u53ea\u7528\u8fd9\u6761\u8bed\u53e5\uff0c\u56e0\u4e3a\u5b83\u7684\u6267\u884c\u53ef\u4ee5\u5ffd\u7565\u4efb\u4f55\u5d4c\u5957\u9650\u5236\u3002<\/p>\n\n\n\n
\u8df3\u8f6c\u7684\u76ee\u6807\u70b9\u53ef\u4ee5\u7531\u4e00\u4e2a\u6807\u793a\u7b26(label)\u6765\u6807\u660e\uff0c\u8be5\u6807\u793a\u7b26\u4f5c\u4e3agoto\u8bed\u53e5\u7684\u53c2\u6570\u3002\u4e00\u4e2a\u6807\u793a\u7b26(label)\u7531\u4e00\u4e2a\u6807\u8bc6\u540d\u79f0\u540e\u9762\u8ddf\u4e00\u4e2a\u5192\u53f7colon (:)\u7ec4\u6210\u3002<\/p>\n\n\n\n
\u901a\u5e38\u9664\u4e86\u5e95\u5c42\u7a0b\u5e8f\u7231\u597d\u8005\u4f7f\u7528\u8fd9\u6761\u8bed\u53e5\uff0c\u5b83\u5728\u7ed3\u6784\u5316\u6216\u9762\u5411\u5bf9\u8c61\u7684\u7f16\u7a0b\u4e2d\u5e76\u4e0d\u5e38\u7528\u3002\u4e0b\u9762\u7684\u4f8b\u5b50\u4e2d\u6211\u4eec\u7528goto\u6765\u5b9e\u73b0\u5012\u8ba1\u6570\u5faa\u73af\uff1a<\/p>\n\n\n\n