C语言语句

if语句

if (condition) {
    doSomething
} elseif(condition) {
    doSomething
} else {
    doSomething
}

例子:
    #include <stdio.h>
    int main()
    {
        char age[3];
        puts("请输入字母:\n");
        scanf("%2s", age);

        if (age[0]=='A') {
            puts(age);
        } else {
            puts("loser");
        }

        return 0;
    }

siwtch语句

switch(variable) {
    case value:
        break;
    default:
}

例子:
    #include <stdio.h>

    int main()
    {
        char test[3];
        scanf("%2s", test);

        switch(test[0]) {
            case 'a':
                puts("this is a");
                break;
            case 'b':
                puts("this is b");
                break;
                default:
                puts("are you ok?");
        }

        return 0;
    }

while语句

while(condition) {
    dosometing
}

例子:
    #include <stdio.h>

    int main()
    {
        int n = 10;
        while (n>=5) {
            printf("输出数字%i\n", n);
            n=n-1;
        }

        return 0;
    }

for语句

for(initial;condition;step) {
    dosometing
}

例子:
    #include <stdio.h>

    int main()
    {
        int n;
        for(n=0;n<10;n++) {
            printf("数字%d\n", n);
        }

        return 0;
    }

需要注意的点

break
    跳出循环

continue
    终端本次循环,进入下一次循环