要点2：循环、条件控制

if(condition) {...} else {...}
if(condition) {...}
if(condition) {...} else if {...} else {...}

switch(variable)
{
    case CASE1:
        ...
        break;
    case CASE2:
        ...
        break;
    default:
        ...
        break;
}

for(;condition;){...}

while(condition) {...}
do{...}while(condition);

#include<stdio.h>

int main()
{
    if(-1) printf("TRUE\n");    // TURE
    return 0;
}