#include <stdio.h>int main( ){ int a=21; int b=10; int c; if( a==b) { printf( "Line1–a等于b\n"); } else { printf( "Line1–a不等于b\n"); } if( a＜b) { printf( "Line2–a小于b\n"); } else { printf( "Line2–a不小于b\n"); } if( a＞b) { printf( "Line3–a大于b\n"); } else { printf( "Line3–a不小于b\n"); } /*改变a和b的值*/ a=5; b=20; if( a＜=b) { printf( "Line4–a小于或等于b\n"); } if( b＞=a) { printf( "Line5–a大于或小于b\n"); }}