200*(1+4.5%)^x大于500则 1.045^x大于2.5 则 X大于 log以1.045为底 2.5 的对数自己用计算器算吧
main(){ int n=0; double zc=2.0E11; float zzl=0.045; while(zc<=5.0E11) { zzl=zzl*1.045; n++; } printf("%d\n",n);}