"c language" programming habits and tricks

Tips:

• The best way to learn an algorithm is not to write a program, but to calculate hand
• Do not figure fast-if not enough time to practice, then learn quickly, forget also fast
• The method of manual simulation focuses on: Record the values of each variable after each statement execution
• Black Box testing: Only the ability to solve problems and not care about what methods are used
• Pseudo-code: in the actual application is not too rigidly tied to the format of pseudo-code, the main purpose is to describe the algorithm outline, avoid details, inspire ideas
• Try to shorten the definition range of variables
• Keep the program simple Keep It Easy and Stupid

1. Exact values

1 Const DoublePI = ACOs (-1.0);//accurate π values2 //Output full square number of all shapes such as AABB. Note: The range of A is 1 ~ 9, but B can be 03 //method One:4  for(intA=0; a<=9; a++) 5 { 6  　　  for(intb=0; b<=9; b++) 7 　　 { 8  　　　　 intn = A *1100+b* One; 9  　　　　 intm = Floor (sqrt (n) +0.5); Ten  　　　　 if(m*m = = N) printf ("%d\n ", N);  One  　　 }  A }  - //the floor function takes only the integer digits, and the decimal place discards - //Floor (x+0.5) in order to round up but such a small part of 0.5 will also have errors the //therefore cannot write if (sqrt (n) = = Floor (sqrt (n))) printf ("%d\n", n); -  - //Method Two: -  for(intx=1;; x + +)  + {  -  　　 intn = x*x; +  　　 if(N < +)Continue;  A  　　 if(N >9999) Break;  at  　　 inthi = n/ -;  -  　　 intLo = n% -;  -  　　 if(hi/Ten= = hi%Ten&& lo/Ten= = lo%Ten) printf ("%d ", N);  -}

"c language" programming habits and tricks